Circuit controlling device



Feb. 9, 1937. J EATQN 2,070,476

GIRciJIT CONTROLLING DEVICE Filed Feb. 4, 1936 Inventor John Ea on, by

His Attorney.

- by. the overload means.

Patented Feb. 2 9, 1937 PATENT OFFICE cmcm'r con'rnoumo DEVICE JohnEaton, Schenectady, N. Y.. assignor to Gen. eral Electric Company, acorporation of New York Application Febllllry 4,1930, scin No. 02,200

s Claims. (c1. zoo-s1) v My invention relates to circuit controllingdevices, more particularly to circuit controlling devices for providingcombined automatic and manual control of electrical apparatus such, forexample, as electric refrigerators, and has for anobject the provisionoi a simple, reliable and inexpensive device of this character.

L Circuit controlling devices of the above type have heretofore beenapplied to electric rei'rigerstem and provided with means for operatingcirciiit controlling contacts between open and closed circuit positionsin accordance with the refrigerator temperaturef to maintain a desiredmean average temperature, with overload responsive r'neans for openingthe contacts to protect the refrigerator motor against excesscurrent-and with manually operable means for opening and closing. thecontacts at will. Much is yet to be desired, however, in providing adevice 01 this type which is compact in its construction and simple andreliable in its operation. Furthermore, it has been found that thecalibration of the overload means may be seriously ai'iected'durmgresetting of the contacts following an overload operation, aconsiderable strain being imposed on the thermal element during thisresetting operation. Accordingly, it is a further object of my inventionto provide a circuit controlling device of the above character providedwith improved resetting means.

. tripping means biased for movement to operate the contact to itsopencircuit position, and restraining means for holding the trippingmeans against operation, the restraining means including a latch membernormally held in one position The overload means is operable in responseto predetermined current conditions to release the latch member andthereby permit movement of the latch member and the tripping member, therestraining means being operable duringsuch movement to return the latchmember to its normal position upon completion of the tripping operation.Manual means are. also provided for returning the tripping member to itsnormal position after the overload means has returned torestrainlngrelation with the latch rnember.

: For a more complete understanding of my-invention, reference shouldnow be had to the drawing'in which Fig. 1 is a perspective view of acircult controlling device embodying my invention;-

and Figs. 2, 8, and 4 are'iragmentary, elevational views of the deviceshown in l 'igi 1, showing the device in different operating positions.

Referring now to the drawing, I have shown my invention as applied to acircuit-controlling device comprising a base member ID provided adjacentone end with a pair of outwardly extending side plates ii and i2 andprovided adJacent the other end with an outwardly extending end plateII. Mounted between the side plates Ii and i2, is an expansible bellowsit, one end of which is secured to the base plate III and connected to asuitable temperature bulb (not shown) by a tube I! (Fig. 2). It will beunderstood of course that the bellows and its associated bulb are iilledwith a suitable, expansibie medium in a manner well known in the art.

As shown, the left-hand end 01' the bellows i4 is arranged to engage apivoted lever it, one end 01' which is mounted on a pin l1 extendingbetween the side plates i i and i2. It will be readily understood bythose skilled in the art, that expension and contraction of the bellowsi4 is e1- iective to operate the lever it about its pivot, and movementoi the lever It in one direction is opposed by a spring it, one end ofwhich is secured to the lever It and the other end of which is securedto an adjustable member I! which extends through the base plate Iii.

The lever It extends through a suitable notch 20 formed in the plate i3and is connected to one end of a U-shaped spring .link 2i, the yokepor-- tion of which is'engaged by the spring 22, the other end of thespring being secured to the yoke of a U-shaped switch member 23, thearms of which are pivotally mounted on pins 24 (only one of which isshown) extending respectively from suitable/lugs which extend outwardlyfrom the end plate I! 'in substantially parallel relation with the sideplates ii and i2. As shown, the yoke end of the spring link 2i extendsthrough a suitable notch 25 in the plate It and as will be more fullyexplained hereinafter, the sides of the notches 20 and 25 provide stopsfor the lever i6 and the spring link 2| respectively. As

shown best in Figs. 2, 3, and 4, one arm or the U-shaped switch member23 i. e. the left hand arm as viewed in Fig. 1 is provided in its lowerend with an extending finger 26 which is arranged to engage the plate i3when'theswitch member 23 is in its open circuit position, shown in Figs.3- and 4, so as to provide a stop for the switch member 23. J

Extending across the U-shaped switch member 23, is a bar 21 and a pairof insulating members 28 and 29. Although the bar 21 and the insulatingmembers 28 and 29 may be secured to the switch member 23 in any suitablemanner, I

prefer to provide the arms of the switch member with extending tangs 30,one of which is shown in Fig. 2, which tangs extend through suitableapertures in the members 21, 28, and 29 and may be overturned to securethese members to the switch member 23. Intermediate its ends, theinsulating member 29 supports an extending finger 3| which, in turn,supports a bridging switch contact member 32 intermediate its ends. Theopposite ends of this bridging contact .member are arranged to engage apair of fixed contacts 33 and 34 which are supported on an insulatingblock 35 suitably secured to the end plate l3.

Resiliently supported on the insulating block 35 by means of a spring36, is a bimetallic element 31 which supports a heating winding 38. Asshown, the free end of the bimetallic element 31 is arranged to engage anotch in one end of an insulating arm 39, the other end of which issecured by rivets 40 to one arm of a bell-crank lever 4| which ispivotally mounted on a pin 42 extending outwardly from the frame. Theother arm of the bellcrank lever 4| supports one end of a bimetallicelement 43, the other end of the bimetallic element 43 being arrangedabuttingly to engage a latch member 44 which is pivotally mounted on apin 45 extending outwardly from the side plate |2 of the frame. As shownbest in Figs. 2, 3, and 4, this latch member 44 pivotally supports oneend of a connecting lever 46, the other end of which is provided with apin 41 extending into a slot 48 formed in a pivoted tripping member 49.This tripping member 49 is pivotally mounted on one of the pins 24 whichsupport the switch member 23 and is provided, as shown, with a slot 50through which the pivot pin 42 extends, the slot 58 being sufficientlylarge so that the tripping member 49 is free to move about its pivotwithout interference from the pivot pin 42.

As shown best in Fig. 1, the side plate I2. is provided with a pair ofaligned slots 5| and 52, and a bifurcated operating member .53 isprovided having cross members 54 and 55 which extend through the slots52 and 5| respectively, the bifurcated member straddling the side plateI2 and being guided thereby for longitudinal movement. One leg of thebifurcated member 53 is provided with a transverse slot 56 through whichan intermediate portion of the lever 46 extends.-

This slot 56 also provides for assembly of the bifurcated member 53 onthe side plate l2 in slidable relation therewith, the slot 56 beingsomewhat wider than the cross portion 51 which separates the slots 5|and 52.

The left-hand end of the bifurcated operating lever 53 is provided, asshown, with a knob 58, and a spring 59, one end of which engages theknob 58 serves to bias the member 53 for operation in a left-handdirection, as viewed in the drawing, the lower end of the spring 59engaging a finger 60 which extends outwardly from the tripping member 49so as to bias the tripping member for rotation in a counterclockwisedirection about its pivot, as viewed in the drawing. The tripping member49 and the bifurcated operating lever 53 are normally restrained in theposition shown in Figs. 1 and 2 byengagement of the pin 41 on theconnecting lever 46 with a shoulder 6| formed on one side of the slot48, the connecting lever 46 engaging the right-hand side of the slot 56to restrain the bifurcated The circuit through the control device may betraced from the connecting lead 62 (Fig. 1) through the fixed contacts33, the bridging contact member 32, the other fixed contact 34, a

conductor63,thebimetallicstrip 31, and the heating winding 38 to theother connecting lead 64. It will thus be seen that the bimetallic strip31 is arranged to be heated in accordance with the current flowing inthe motor circuit, and as will 'be understood by those skilled in theart, the

bimetallic element 43 which is affected only by ambient temperatureconditions, serves to compensate for deflection of the bimetallicelement 31 in response to ambient temperature changes so that theoverload tripping means will at all times be responsive to apredetermined value of motor current.

With the control device in the operating position shown in Figs. 1 and2, it will be seen that the motor circuit is completed through thecontacts 33, 32, and 34, and accordingly, the refrigerator is operatingto provide a gradually decreasing temperature. When the refrigeratortemperature has decreased to the desired value, the bellows I 4 willhave contracted and the spring l8 will operate the lever IS in aclockwise direction about its pivot. As the lever I 6 moves in thisdirection, it will be seen that the upper end of the U-shaped springlink will be moved toward the spring 22, and accordingly, the spring 22will be stressed. As the arms of the spring link 2| move past the lineof action of the spring 22, the spring will exert a force on the springlink 2| tending to rotate the spring link about its pivot in a.clockwise direction, the yoke end of the spring link moving from theposition shown to a position in which itengages the other side of theslot 25. Accordingly, the lower end of the spring 22 is moved from theposition shown in which it exerts a force on the switch member 23tending to rotate the switch member in a clockwise direction about itspivot 24 to a position in which the spring 22 exerts a'force on theswitch member 23 tending to rotate it in a counterclockwise directionabout its pivot. The switch member 23 will, therefore, be moved with asnap action to disengage the bridging member 32 from the fixed contacts33 and 34. The construction and the operation of the mechanism foroperating the contacts in response to changes of refrigeratortemperature comprise no part of the present invention, and are fullydescribed and claimed in United States Patent No. 1,921,126 issuedAugust 8, 1933 to Leonard P. Hutt.

It will be understood of course that consequent to the opening of thecircuit controlling contacts, the refrigerator motor will be stopped,and accordingly, the temperature of the refrigerator will increase so asto expand the bellows l4 and upon a predetermined expansion of thebellows l4, the contacts will be operated to the closed circuit positionin a manner similar to that described above.

It will now be assumed that with the control device in the positionsshown injigs. 1 and 2, a current of overload magnitude fiifiws in themotor circuit. This current flowing through the bimetallic element 31and the heating winding 38 so heats the bimetallic element as to causethe free end of the element to move in a right-hand direction,-as viewedin the drawing. Accordingly, the bellcrank lever 4| will be rotated in aclockwise direction about its pivot, and the free end of the bimetallicelement 43 will move in a left-hand direction out of engagement with thelatch member 44. It will be remembered that the tripping member isbiased by the spring 59 for movement in a counterclockwise directionabout its pivot and since this bias is transferred to the latch member44 through the connecting lever 46, it will be apparent that as soon asthe bimetallic element 43' moves out of engaging relation with the latchmember 44, the spring 59 will be efiective to rotate the tripping member49 and the latch member 44, the connecting link 46 being moved upwardlyduring rotation of these members.

As the tripping member 49 rotates in a counterclockwise direction, afinger formed thereon engages the insulating member 28 carried by theswitch member 23 and operates the switch member 23 to the open circuitposition shown in Fig. 3. In Fig. 3, the tripping member 49, theconnecting lever 46 and the latch member 44 are shown in the positionswhich they assumed at the instant immediately following separation ofthe contacts. and it will be seen that in this position,

member 53 to the connecting lever 46 is suificient to move the pin 41over the shoulder 6| As soon as the pin 41 moves past the shoulder, theconnecting lever 46 is released for movement about its pivotalconnection to the latch 44, and

accordingly, the spring 59 moves the operating lever 53 in a left-handdirection to the position shown in Fig. 4. During this movement of theoperating lever 53, the pin 41 engages the upper side of the slot 48,and a cam action is thereby exerted on the pin 41 which is effective tomove the lever 46 downwardly to the position shown in Fig. 4, so as toreturn the latch member 44 to the position there shown. tends outwardlyfrom the plate l2, as shown best in Fig. 1, serves as a stop to maintainthe latch member 44in the position shown in Fig. 4.

Operation of the contacts to the open. circuit position will of courseeffect deenergization of the heater 39 and as the bimetallic element 31cools, it will be apparent that the bimetallic element 43 is free toreturn to its normal latching position without interference from thelatch member 44. Accordingly, the calibration of the control device willnot be effected during the resetting operation, since no strain isimposed on either the bimetallic element 32 orthe bimetallic element 43.After the bimetallic element 31 has cooled and the bimetallic element 43has returned to the position shown in Fig. 4, the tripping member may bereset by depressing the switch button 58 so as to move the operatinglever 53 in a righthand direction. This movement of the member 53 willcause the left-hand edge of the slot 56 to engage the connecting lever46 and rotate the connecting lever in a clockwise direction about itspivot, so as to move the pin 41 in a right-hand direction along thelower edge of the slot 48.

passing over the shoulder 6|.

The pin l1 which ex- During this movement, the pin 41 exerts a camaction on the tripping member 49, so as to rotate the tripping member ina clockwise direction about its pivot to the position shown in Fig. 2,the pin 41 at the end of the resetting movement Since the" spring 59 iscompressed during this resetting operation. the pin 41 will be retainedin engagement with the shoulder 6| by the force exerted on the trippingmember and on the lever 48. and accordingly, the parts will be held inthe positions shown in Fig. 2 when the push button 58 is released.

Although the latching engagement between the pin 41 and the shoulder 6|is sufficient to prevent movement of the lever 46 and the trippingmember 49 by the spring 59, the control device may be manually operatedto the open circuit position by simply exerting a sufilcient force onthe push button 58 in a left-hand direction to'force the pin 41 over thecrest of the shoulder 6|. As soon as the pin 41 is released from theshoulder 6|, the spring 59 will assist in moving the tripping member andthe connecting lever 49 to the position shown in Fig. 4, whereby theswitch member' 23 will be operated to the open circuit position.

It will be apparent that my improved control device is entirelytrip-free, i. e. operation of the contacts to the open circuit positionin response to an overload cannot be prevented by holding the pushbutton 59 in its depressed position. If the push button 58 is so held,the parts will move to the position shown inFig. 3 upon the occurrenceof an overload condition, and the resetting action of the connectinglever 48 in regard to the lever 44 will not take place until the pushbutton 58 is released. The circuit controlling contacts, however, moveto the open circuit position shown in Fig. 3.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto sincemany modifications may be made and I, therefore, contemplate by theappended claims to cover any such modifications as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. A circuit controlling device comprising contacts one of which ismovabfe between open and closed circuit positions, a tripping memberpivotally mounted for rotation to cause operation of said one contact tosaid open circuit position, a normally restrained latch member, aconnecting lever pivotally secured to said latch member,

means biasing said lever and said tripping member for rotation abouttheir respective pivots, a releasable connection between said lever andsaid tripping member for restraining said lever and said tripping memberagainst movement so long as said latch member is restrained, overloadmeans for releasing said latch member whereupon said tripping memberrotates in accordance with its bias to operate said one contact and torelease said connecting lever, and means responsive to the consequentrotation of said connecting lever in accordance with its bias forreturning said latch member to its normal position.

2. A circuit controlling device comprising con- K tacts one of which ismovable between open and closed circuit positions, a tripping memberpivotally mounted for rotation to cause operation of said one contact tosaid open circuit position, a normally restrained latch member, aconnecting lever pivotally secured to said latch member, means includinga single biasing spring for bias- 4f Y v apron-7e ing said lever andsaid tripping member for rotation about their respective pivots, alatching connection between said lever and said tripping memberincluding cooperating 'cam surfaces for restraining said lever and saidtripping member against movement so long as said latch member isrestrained, overload means for releasing said latch member whereuponsaid tripping member rotates in accordance with its bias to operate saidone contact, said rotation of said tripping member causing relativemovement between said cam surfaces to release said lever for rotationabout its pivot, and means responsive to rotation of. said lever forreturning said latch member to its normal position.

3. A circuit controlling device comprising contacts one of which ismovable between open and closed circuit positions, means for operatingsaid one contact between said positions, a tripping member pivotallymounted for rotation to cause operation of said one contact to openposition independently of said operating means, 2. normally restrainedlatch member, a connecting lever pivotally secured to said latch member,means biasing said lever and said tripping member for rotation abouttheir respective pivots, a releasable connection between said lever andsaid tripping member including cooperating cam surfaces forrestrainingsaid lever and said tripping member against movement by saidbiasing means so long as said latch member is restrained, overload meansfor releasing said latch member to permit operation of said trippingmember, and manual means for moving said lever to force said camsurfaces out of engagement whereby said tripping member is released foroperation independently of said restrained latch member.

4. A circuit controlling device comprising a tripping member having acam surface thereon, a latch member, a connecting lever having one endpivotally secured to said latch member and its other end engaging saidcam surface, means for biasing said lever for movement about its pivotto move said other end along said cam surface, a shoulder on said camsurface engaging said end to restrain said lever against pivotalmovement, means biasing said tripping member for movement from a normalposition to a tripped position and current responsive means normallyrestraining said latch member against movement whereby said connectinglever restrains said tripping member against movement,

said current responsive means being operable to release said latchmember whereupon said tripping member is operated to its trippedposition by its biasing meansrthe relative movement of said trippingmember and said connecting lever during said operation releasing saidlever from said shoulder for operation about its pivot in accordancewith its bias, said cam surface and said lever cooperating duringpivotal operation of said lever to return said latch member to itsnormal position.

5. A circuit controlling device comprising a tripping member having acam slot therein, a latch member, a connecting lever having one endpivotally secured to said latch member, a pin supported on the other endof said lever and extending within said cam slot, means biasing saidlever for movement about its pivot to move said pin along said slot. ashoulder on one side of said slot engaging said pin to restrain saidlever against pivotal movement, means biasing said tripping member formovement from a normal position to a tripped position, and currentresponsive means normally restraining said latch member against movementwhereby said connecting lever restrains said tripping member, saidcurrent responsive means being operable to remember is operated to itstripped position by its biasing means, the relative movement of saidtripping member and said connecting lever during said operationreleasing said pin from said shoulder whereupon said lever is operatedabout its pivot by its biasing means, said cam slot and said pincooperating during said pivotal movement of said lever. to return saidlatch member to its normal position.

6. A circuit controlling device comprising a pivoted tripping memberhaving a cam slot therein, a pivoted latch member, a connecting leverhaving one end pivotally secured to said latch member, a pin supportedon the other end of said lever and extending within said cam slot, anoperating member arranged to engage an intermediate portion of saidlever, a biasing spring arranged to bias said tripping member formovement from a normal position to a tripped position and to bias saidoperating member for movement in one direction to operate said leverabout its pivot, a shoulder formed on one side of said slot engagingsaid pin to restrain said lever against pivotal movement, overload meansnormally restraining said latch member against movement whereby saidconnecting lever restrains said tripping member, said overload meansbeing operable on overload to release said latch member whereupon saidtripping member is operated to its tripped position by said biasingspring, the relative movement of said tripping member and said leverduring said operation releasing said pin from said shoulder whereuponsaid operating member moves said lever about its pivot, said cam slotand said pin cooperating during said pivotal movement to return saidlatch member to its normal position, and manual means for moving saidoperating member in an opposite direction to move said lever about itspivot and return said pin to its normal engaging relation with saidshoulder, said slot and said pin cooperating'to return said trippingmember to its normal position.

'7 A circuit controlling device comprising a pivoted tripping memberhaving a cam slot therein, a pivoted latch member, a connecting leverhaving one end pivotally secured to said latch member, a pin supportedon the other end of said lever engaging said cam slot whereby said leveris moved longitudinally as said members rotate about their respectivepivots, an operating member slidable transversely of said lever andhaving a portion arranged abuttingly to engage said lever, a biasingspring arranged to bias said tripping member for rotation to a trippedposition and to bias said operating member for movement in one directionto operate said lever about its pivot, a shoulder in said slot engagingsaid pin to restrain said lever against pivotal movement, latching meansincluding a thermal element normally restraining said latch memberagainst movement whereby said connecting lever restrains said trippingmember, said thermal element when heated being operable to release saidlatch member whereupon said tripping element is operated to its trippedposition by said biasing spring, said lever moving longitudinally assaid tripping member rotates to release said pin from said shoulderwhereupon said operating member is moved by said spring to operate saidlever about its pivot, said pin engaging a side of said cam slot duringsaid pivotal operation to move said lever longitudinally and return saidlatch member to its normal position for reengagement with said latchingmeans when said thermal element cools, and manual means for moving saidoperating member against the bias of said spring to move said leverabout its pivot, said pivotal movement being effective when said latchmember is restrained by said latching means to return said pin to itsnormal engaging relation with said shoulder, said pin engaging anotherside of said cam slot during said movement to return said trippingmember to its normal position.

8. A circuit controlling device comprising a movable control lever, alatch member mounted for movement from one position to a secondposition, means pivotally mounting one end of said lever on said latchmember whereby longitudinal movement of said lever operates said latchmember between said positions, current responsive means for normallylatching said latch member in said one position, a pivoted trippingmember having a cam slot therein shaped to provide a shoulder, means forbiasing said tripping member for movement from a normal position to atripped position, said lever having its other end extending into saidslot and engaging said shoulder to restrain said tripping member againstmovement to said tripped position, an operating member movable to engagean intermediate portion of said control lever, means for biasing saidoperating member for movement in a direction to rotate said lever aboutits pivot, said shoulder preventing said rotation of said lever, saidcurrent responsive means being effective to release said latch member inresponse to predetermined current conditions whereupon the biasing forceon said tripping member operates said tripping member to said trippedposition and thereby operates said control lever longitudinally to movesaid latch member to said second position, said operation of saidtripping member and said control lever releasing said lever fromengagement with said shoulder whereupon said operating member moves inaccordance with its bias to rotate said control lever about its pivot,and means including said cam slot for moving said lever longitudinallyin response to rotation thereof to return said latch member to said oneposition.

JOHN EATON.

